From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3E9AC677F1 for ; Thu, 12 Jan 2023 20:54:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233742AbjALUyo (ORCPT ); Thu, 12 Jan 2023 15:54:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240459AbjALUx2 (ORCPT ); Thu, 12 Jan 2023 15:53:28 -0500 Received: from mail-ej1-f51.google.com (mail-ej1-f51.google.com [209.85.218.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 932AE17581; Thu, 12 Jan 2023 12:31:55 -0800 (PST) Received: by mail-ej1-f51.google.com with SMTP id mp20so1004821ejc.7; Thu, 12 Jan 2023 12:31:55 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=L2nFgdDb65kynrrmfmzSLp/jRdwKd3Nk1yZl/VPrHZs=; b=DN5b560iNswoycqndzNzb8swfw01ooPIMdVp3pe5EaSOknyKsO59E92VttsBN73Lwt iLIVBWyje3HZfwa9FrGsEdiMdBfpqdKizVltKyuo2mUpTix7oUTvOioQGOjpejT31hBb 8SuG8SP0dNcbDPMvxyaEmz/iEaprz01LPQyYONePTtB5QELDa+Xzti7QfK/kdvXZ7j15 SagVHfUVg3K8ItGz0TGrSgrL9dBASVfXJKQpRuyLL4WJQXnMMOjkK7odYtWaABNmOO8E /liy/AVdcmZZ7gBlBQDh2Wpq+/7UlGV6iAo2ve3js8/GfxtXAKntBSVf8DSEQeRLGVMz l0PA== X-Gm-Message-State: AFqh2kp8+Cv1srM08aZsN5AusUJkje/VBcfvyY00c2HIr7jj47P5qODV awFuMc8wWM0+Nvdg8C/CFZI1JxlPfxiuHqD6m6g= X-Google-Smtp-Source: AMrXdXvN5SBlmpldVVXQjqra/kzAOUvvwIr688rrELNMvTTVMYkAJOEGgxACXyoLu4sLkPSJ8TokhYn7N2hye/e40VY= X-Received: by 2002:a17:907:75ea:b0:7c0:f118:7e4e with SMTP id jz10-20020a17090775ea00b007c0f1187e4emr4485732ejc.478.1673555514054; Thu, 12 Jan 2023 12:31:54 -0800 (PST) MIME-Version: 1.0 References: <5659681.DvuYhMxLoT@kreacher> <20230112202132.GA1788706@bhelgaas> In-Reply-To: <20230112202132.GA1788706@bhelgaas> From: "Rafael J. Wysocki" Date: Thu, 12 Jan 2023 21:31:42 +0100 Message-ID: Subject: Re: [PATCH v3] PCI / ACPI: PM: Take _S0W of the target bridge into account in acpi_pci_bridge_d3(() To: Bjorn Helgaas Cc: "Rafael J. Wysocki" , linux-pci@vger.kernel.org, "Limonciello, Mario" , "Rafael J. Wysocki" , Len Brown , Bjorn Helgaas , Mika Westerberg , Mehta Sanju , Lukas Wunner , "Rafael J . Wysocki" , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Linux PM Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Jan 12, 2023 at 9:21 PM Bjorn Helgaas wrote: > > On Wed, Jan 11, 2023 at 11:38:55AM +0100, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > > > It is generally questionable to allow a PCI bridge to go into D3 if > > it has _S0W returning D2 or a shallower power state, so modify > > acpi_pci_bridge_d3(() to always take the return value of _S0W for the > > target bridge into accout. That is, make it return 'false' if _S0W > > returns D2 or a shallower power state for the target bridge regardless > > of its ancestor PCIe Root Port properties. Of course, this also causes > > 'false' to be returned if the PCIe Root Port itself is the target and > > its _S0W returns D2 or a shallower power state. > > > > However, still allow bridges without _S0W that are power-manageable via > > ACPI to enter D3 to retain the current code behavior in that case. > > > > Link: https://lore.kernel.org/linux-pci/20221031223356.32570-1-mario.limonciello@amd.com/ > > Reported-by: Mario Limonciello > > Signed-off-by: Rafael J. Wysocki > > --- > > > > v2 -> v3: > > * Use rpadev for the ACPI companion of the Root Port in acpi_pci_bridge_d3(() > > to avoid confusion. > > * Make the function evaluating _S0W return the value produced by it or "unknown > > state" on errors and let its caller deal with that value. > > > > --- > > drivers/acpi/device_pm.c | 19 +++++++++++++++++++ > > drivers/pci/pci-acpi.c | 45 +++++++++++++++++++++++++++++++-------------- > > include/acpi/acpi_bus.h | 1 + > > 3 files changed, 51 insertions(+), 14 deletions(-) > > > > Index: linux-pm/drivers/pci/pci-acpi.c > > =================================================================== > > --- linux-pm.orig/drivers/pci/pci-acpi.c > > +++ linux-pm/drivers/pci/pci-acpi.c > > @@ -976,24 +976,41 @@ bool acpi_pci_power_manageable(struct pc > > bool acpi_pci_bridge_d3(struct pci_dev *dev) > > { > > struct pci_dev *rpdev; > > - struct acpi_device *adev; > > - acpi_status status; > > - unsigned long long state; > > + struct acpi_device *adev, *rpadev; > > const union acpi_object *obj; > > > > if (acpi_pci_disabled || !dev->is_hotplug_bridge) > > return false; > > > > - /* Assume D3 support if the bridge is power-manageable by ACPI. */ > > - if (acpi_pci_power_manageable(dev)) > > - return true; > > + adev = ACPI_COMPANION(&dev->dev); > > + if (adev) { > > + /* > > + * If the bridge has _S0W, whether or not it can go into D3 > > + * depends on what is returned by that object. In particular, > > + * if the power state returned by _S0W is D2 or shallower, > > + * entering D3 should not be allowed. > > + */ > > + if (acpi_dev_power_state_for_wake(adev) <= ACPI_STATE_D3_HOT) > > The comment suggests that this should check for "<= ACPI_STATE_D2" > (not ACPI_STATE_D3_HOT). Or is there some subtlety here that I'm > missing? No, this is a mistake. I'll send a v4.